This invention relates to a moisture detector, particularly, but not exclusively, for detecting urine.
It is already known, e.g. from GB 2 219 679 A, to use a battery-operated moisture detector in a babies nappy (diaper). When the nappy becomes wet a radio signal is sent to a remote indicator which generates an audible signal to indicate that the nappy requires changing.
The present invention seeks to provide a new and inventive form of moisture detector.
The present invention proposes a moisture detector comprising a detector unit which is arranged to operate a remote alarm via a wire-less link when moisture is present, in which the detector unit is powered by electrical charge stored in capacitor means.
The capacitor means may comprise a single capacitor or a bank of capacitors.
In a preferred form the detector unit comprises a sealed liquid-impermeable housing containing said capacitor means, and an external moisture sensor.
The moisture sensor preferably comprises a pair of moisture-sensing electrodes. In a preferred form of the device the moisture-sensing electrodes are remote from the housing of the detector unit. The electrodes are preferably incorporated in a moisture-absorbent tail and are preferably formed by depositing an electrically-conductive ink onto a flexible moisture-absorbent strip.